existed and worked. Next to this come certain treatises written in prose and verse called the Upaniṣads, which contain various sorts of philosophical thoughts mostly monistic or singularistic but also some pluralistic and dualistic ones. These are not reasoned statements, but utterances of truths intuitively perceived or felt as unquestionably real and indubitable, and carrying great force, vigour, and persuasiveness with them. It is very probable that many of the earliest parts of this literature are as old as 500 B.C. to 700 B.C. Buddhist philosophy began with the Buddha from some time about 500 B.c. There is reason to believe that Buddhist philosophy continued to develop in India in one or other of its vigorous forms till some time about the tenth or eleventh century A.D. The earliest beginnings of the other Indian systems of thought are also to be sought chiefly between the age of the Buddha to about 200 B.C. Jaina philosophy was probably prior to the Buddha. But except in its earlier days, when it came in conflict with the doctrines of the Buddha, it does not seem to me that the Jaina thought came much in contact with other systems of Hindu thought. Excepting in some forms of Vaiṣṇava thought in later times, Jaina thought is seldom alluded to by the Hindu writers or later Buddhists, though some Jains like Haribhadra and Guṇaratna tried to refute the Hindu and Buddhist systems. The non-aggressive nature of their religion and ideal may to a certain extent explain it, but there may be other reasons too which it is difficult for us to guess. It is interesting to note that, though there have been some dissensions amongst the Jains about dogmas and creeds, Jaina philosophy has not split into many schools of thought more or less differing from one another as Buddhist thought did.
The first volume of this work will contain Buddhist and Jaina philosophy and the six systems of Hindu thought. These six systems of orthodox Hindu thought are the Sāṃkhya, the Yoga, the Nyāya, the Vaiśeṣika, the Mimāṃsā (generally known as Purva Mimāṃsā), and the Vedānta (known also as Uttara Mimāṃsā). Of these what is differently known as Sāṃkhya and Yoga are but different schools of one system. The Vaiśeṣika and the Nyāya in later times became so mixed up that, though in early times the similarity of the former with Mimāṃsā was greater than that with Nyāya, they came to be regarded as fundamentally almost the same systems. Nyāya and Vaiśeṣika have therefore been treated
